The present invention relates generally to a method of generating hoistway information to serve an elevator control and, in particular, to a method of generating hoistway information from an elevator hoistway with an elevator car that can travel in the hoistway, the hoistway information being generated from pictorially recognizable patterns.
The European patent specification EP 0 722 903 B1 shows a device for generating hoistway information from an elevator hoistway. In the elevator hoistway a reflector with a code is arranged in the vicinity of a stop for an elevator car. The code has two identical tracks. An approach zone of the stop, in which bridging of door contacts is allowed, lies half above and half below a leveling line. An adjusting zone, in which adjustment of an elevator car which is too low due to rope stretch is allowed with open car doors, lies half above and half below the leveling line. The code of the tracks is read and analyzed by a 2-channel analyzing device arranged on the elevator car. Transmitters of the analyzing device illuminate the tracks of the reflector. The illuminated surfaces of the tracks are captured on CCD sensors of the analyzing device and imaged by means of pattern recognition logic. Transformation of the images into information to serve the elevator control takes place by means of a computing device.
A disadvantage of this known device is that a code strip arranged in the elevator hoistway is necessary to generate patterns. The code strip must be arranged in the elevator hoistway precisely and without excessive stretching. Furthermore, it is not guaranteed that the code strip will not wholly or partly separate from the underlying support surface. Incorrect mounting or detachment of the code strip results in no, or incorrect, patterns.
The present invention provides a solution for avoiding the disadvantages of the above-described known device and proposes a system and a method with which generation of hoistway information serving an elevator control is guaranteed in all cases.
The method according to the present invention generates elevator hoistway information to an elevator control for an elevator car travelling in the hoistway comprising the steps of: a. providing a sensor on an elevator car travelling in a hoistway; b. sensing with the sensor pictorially recognizable patterns on at least one existing component of the hoistway, the existing component serving a function related to the hoistway other than proving the patterns; and c. generating from the patterns an absolute position signal representing an actual position of the elevator car in the hoistway. Step b. can be performed by generating images of sectors of the patterns and an incremental position of a current one of the images with respect to a preceding one of the images, and step c. can be performed by determining an absolute position of the current image from the incremental position and an absolute position of the preceding image.
The advantages achieved by means of the present invention include that no additional installation is needed in the hoistway. The installation time for the elevator can thereby be substantially shortened. An analyzing device provided with sensors and arranged on the elevator car suffices to generate the hoistway information. A very reliably operating and inexpensive hoistway information system with high resolution can be realized with the structures present in the elevator hoistway. The hoistway information system delivers an absolute position at startup without the elevator car traveling. Moreover, the system can store floor stopping positions and simulate the hoistway switches used hitherto for, for example, brake application, door zones, and emergency stopping, or other hoistway switches. The system is therefore compatible with existing elevator controls.